When a person suffers a cardiac arrest either inside or outside the hospital, the chances of survival are small. See L. Becker et al., Ann. Emerg. Med. 20, 355-361 (1991). One of the major reasons for this poor outcome is the fact that chest compression during basic cardiopulmonary resuscitation (CPR) results in little forward blood flow. Though certain drugs, like epinephrine, have been shown to improve vital organ blood flow during CPR, they are given almost exclusively into a vein and therefore, must slowly circulate to the heart, through the heart and lungs, and finally to the peripheral arteries where their major beneficial effects occur. During this circulation time, the heart and brain continue to receive blood flow which cannot sustain cellular survival. Invasive techniques such as open-chest cardiac massage (OCCM), direct mechanical ventricular assistance (DMVA), and cardiopulmonary bypass (CPB) provide better vital organ blood flow. See generally R. Bartlett et al., Ann. Emerg. Med. 13 (Part 2), 773-777 (1984); M. Anstadt et al., Resuscitation 21, 7-23 (1991); P. Safar et al., Am. J. Emerg. Med. 8, 55-67 (1990). However, adapting these techniques for widespread use in the pre-hospital setting seems unlikely. In most cases, the window of time allowing for good neurologic recovery would likely run out before these techniques could be employed in the emergency department.
The inventions disclosed herein are based upon ongoing research into means by which the survival rates of sudden, out-of-hospital, cardiac arrest may be increased.